These investigations will isolate and characterize the remaining uncharacterized apoproteins of human plasma triglyceride rich lipoproteins from normals and patients with lipid transport abnormalities. They will describe the kinetic properties of each of these apoproteins by in vivo studies of normal humans and contrast this with patients who have disorders of plasma lipid tRansport. The relationship of the arginine rich apoprotein to heparin and in turn to lipoprotein lipase will be determined. The functional properties of the apoproteins with regard to the plasma catabolism and the hepatic assembly and secretion of these lipoproteins will be detailed Modifications of these apoproteins will be made and their effect on function and kinetic behavior of the lipoproteins investigated. The functional roles of the apoprotein will be defined in plasma exzyme assays relating to the catabolism of the lipoprotein, and assays for hepatic synthesis of lipid, assembly and secretion of lipoproteins.